Saffron odorants

ABSTRACT

The present invention concerns a compound of formula (I), in the form of any one of its stereoisomers or a mixture thereof, and wherein the dotted line represents a carbon-carbon single or double bond; as well as its use as perfuming ingredient.

TECHNICAL FIELD

The present invention relates to the field of perfumery. Moreparticularly, it concerns a compound of formula

as defined herein below, as well as its use as perfuming ingredient. Thepresent invention concerns also the invention's compound as part of aperfuming composition or of a perfuming consumer product.

PRIOR ART

To the best of our knowledge, none of the invention's compounds is knownin the prior art. Perfuming ingredients having saffron odors areespecially interesting for the perfumery industry.

The present invention's compounds are structurally related to the ironesand ionones families, which are well known perfuming ingredients. Allknown irones and ionones used in perfumery have odors characterized byviolette/orris or woody/fruity odors respectively, i.e. very differentodors, and none of them has been reported or suggested as having even aslight saffron tonality (see Table 1 in the description).

Therefore, the odor properties of the present compounds are totallyunexpected, especially considering that the structurally closestanalogues having a saffron character are structurally very different(see Table 1 in the description).

DESCRIPTION OF THE INVENTION

We have now surprisingly discovered that a compound of formula

-   -   in the form of any one of its enantiomers or a mixture thereof,        and wherein the dotted line represents a carbon-carbon single or        double bond having predominantly a configuration E;        can be used as perfuming ingredient, for instance to impart odor        notes of the saffron type together with aspects of the        methylionone/orris type.

For the sake of clarity, by the expression “any one of its enantiomers”,or the similar, it is meant the normal meaning understood by a personskilled in the art, i.e. that the invention's compound can be a pureenantiomer.

For the sake of clarity, by the expression “having predominantly aconfiguration E”, or the similar, it is meant the normal meaningunderstood by a person skilled in the art, i.e. that the invention'scompound can be in the form of a mixture of diasteroisomers ofconfiguration E or Z wherein the E isomer account for at least 60% w/wof said mixture, more advantageously at least 80% or 90% w/w, percentagebeing relative to the total weight of said mixture.

For the sake of clarity, by the expression “wherein the dotted linerepresents a carbon-carbon single or double bond”, or the similar, it ismeant the normal meaning understood by a person skilled in the art, i.e.that the whole bonding (solid and dotted lines) between the carbon atomsconnected by said dotted line, e.g. carbon 3 and 4, is a carbon-carbonsingle or double bond.

According to an embodiment of the invention, said compound (I) is4-(2,5,6,6-tetramethylcyclohexa-1,3-dienyl)-but-3-en-2-one (i.e. thedotted line represents a carbon-carbon double bond). In particular, said4-(2,5,6,6-tetramethylcyclohexa-1,3-dienyl)-but-3-en-2-one can be in theform of a mixture of (E) and (Z) isomers wherein the (E) isomerrepresents at least 60% w/w, or even at least 80% w/w, relative to thetotal weight of said mixture.

As specific example of the invention's compounds, one may cite, asnon-limiting example,(E)-4-(2,5,6,6-tetramethylcyclohexa-1,3-dienyl)-but-3-en-2-one.

The compounds of formula (I) are also novel compounds, and therefore arealso an object of the present invention.

Table 1 herein below reports the odor properties of the invention'scompounds and, for comparison, the odor properties of prior artanalogues and of other analogues not yet reported in the literature:

TABLE 1 Invention's compounds and their odor properties Compoundstructure and name Odor notes Present invention

Predominantly saffron odor, with powdery nuance. Its odor is an unusualduality of saffron notes and an orris nuance which results in a spicy-oriental powdery character evoking saffron with a cosmetic twist (of theface powder type)

A balanced saffron and methylionone odor. Its odor is clearly saffronlike, although the saffron note and the methyl ionone notes are ofsimilar strength Comparative examples

Orris, powdery, very natural No saffron notes

Metallic, powdery, woody No saffron notes Examples of known Ionones andIrones

Floral (orris/violet), sweet, odor with moderate tenacity No saffronnotes

Powdery, woody odor No saffron notes

Similar to alpha irone but more powerful No saffron notes

Orris, violet-like, sweet and diffusive odor No saffron notes Closestknown analogues known to have a saffron note

Mirabelle, damascenone, woody-saffron

Saffron

Saffron

When the odor of the invention's compounds is compared with that of theprior art ionones or irones, then the invention's compounds distinguishthemselves by having a saffron character, the latter being totallyabsent in the prior art ionones or irones. Furthermore, the invention'scompounds distinguish themselves from some prior art ionones or ironesby lacking the woody notes so characteristic of some of said prior artcompound(s).

The fact that the invention's compounds possess a saffron note which isdominant, or as powerful, compared to the other notes, renders saidcompounds and the ionones/irones suitable for different uses, i.e. toimpart different organoleptic impressions. Indeed the closest analoguesof the ionones and irones could not be used to impart saffron type notesor characters.

As mentioned above, the invention concerns the use of a compound offormula (I) as perfuming ingredient. In other words, it concerns amethod to confer, enhance, improve or modify the odor properties of aperfuming composition or of a perfumed article, which method comprisesadding to said composition or article an effective amount of at least acompound of formula (I). Understood that the exact final hedonic effect,provided by said method or use, may depends on the precise dosage of theinvention's compound and on the organoleptic properties of the initialperfumed composition, but anyway the addition of the compound willimpart to the final product its typical character in the form of a note,touch or aspect depending on the dosage.

By “use of a compound of formula (I)” it has to be understood here alsothe use of any composition containing a compound (I) and which can beadvantageously employed in perfumery industry.

Said compositions, which in fact can be advantageously employed asperfuming ingredients, are also an object of the present invention.

Therefore, another object of the present invention is a perfumingcomposition comprising:

-   i) as perfuming ingredient, at least one invention's compound as    defined above;-   ii) at least one ingredient selected from the group consisting of a    perfumery carrier and a perfumery base; and-   iii) optionally at least one perfumery adjuvant.

By “perfumery carrier” we mean here a material which is practicallyneutral from a perfumery point of view, i.e. that does not significantlyalter the organoleptic properties of perfuming ingredients. Said carriermay be a liquid or a solid.

As liquid carrier one may cite, as non-limiting examples, an emulsifyingsystem, i.e. a solvent and a surfactant system, or a solvent commonlyused in perfumery. A detailed description of the nature and type ofsolvents commonly used in perfumery cannot be exhaustive. However, onecan cite as non-limiting example solvents such as dipropyleneglycol,diethyl phthalate, isopropyl myristate, benzyl benzoate,2-(2-ethoxyethoxy)-1-ethanol or ethyl citrate, which are the mostcommonly used. For the compositions which comprise both a perfumerycarrier and a perfumery base, other suitable perfumery carriers thanthose previously specified, can be also ethanol, water/ethanol mixtures,limonene or other terpenes, isoparaffins such as those known under thetrademark Isopar® (origin: Exxon Chemical) or glycol ethers and glycolether esters such as those known under the trademark Dowanol® (origin:Dow Chemical Company).

As solid carrier one may cite, as non-limiting examples, absorbing gumsor polymers, or yet encapsulating materials. Examples of such materialsmay comprise wall-forming and plasticizing materials, such as mono, di-or trisaccharides, natural or modified starches, hydrocolloids,cellulose derivatives, polyvinyl acetates, polyvinylalcohols, proteinsor pectins, or yet the materials cited in reference texts such as H.Scherz, Hydrokolloids: Stabilisatoren, Dickungs- and Gehermittel inLebensmittel, Band 2 der Schriftenreihe Lebensmittelchemie,Lebensmittelqualität, Behr's VerlagGmbH & Co., Hamburg, 1996. Theencapsulation is a well known process to a person skilled in the art,and may be performed, for instance, using techniques such asspray-drying, agglomeration or yet extrusion; or consists of a coatingencapsulation, including coacervation and complex coacervationtechniques.

By “perfumery base” we mean here a composition comprising at least oneperfuming co-ingredient.

Said perfuming co-ingredient is not of formula (I). Moreover, by“perfuming co-ingredient” it is meant here a compound, which is used ina perfuming preparation or a composition to impart a hedonic effect. Inother words such a co-ingredient, to be considered as being a perfumingone, must be recognized by a person skilled in the art as being able toimpart or modify in a positive or pleasant way the odor of acomposition, and not just as having an odor.

The nature and type of the perfuming co-ingredients present in the basedo not warrant a more detailed description here, which in any case wouldnot be exhaustive, the skilled person being able to select them on thebasis of his general knowledge and according to intended use orapplication and the desired organoleptic effect. In general terms, theseperfuming co-ingredients belong to chemical classes as varied asalcohols, lactones, aldehydes, ketones, esters, ethers, acetates,nitriles, terpenoids, nitrogenous or sulphurous heterocyclic compoundsand essential oils, and said perfuming co-ingredients can be of naturalor synthetic origin. Many of these co-ingredients are in any case listedin reference texts such as the book by S. Arctander, Perfume and FlavorChemicals, 1969, Montclair, N.J., USA, or its more recent versions, orin other works of a similar nature, as well as in the abundant patentliterature in the field of perfumery. It is also understood that saidco-ingredients may also be compounds known to release in a controlledmanner various types of perfuming compounds.

By “perfumery adjuvant” we mean here an ingredient capable of impartingadditional added benefit such as a color, a particular light resistance,chemical stability, etc. A detailed description of the nature and typeof adjuvant commonly used in perfuming bases cannot be exhaustive, butit has to be mentioned that said ingredients are well known to a personskilled in the art.

An invention's composition consisting of at least one compound offormula (I) and at least one perfumery carrier represents a particularembodiment of the invention as well as a perfuming compositioncomprising at least one compound of formula (I), at least one perfumerycarrier, at least one perfumery base, and optionally at least oneperfumery adjuvant.

It is useful to mention here that the possibility to have, in thecompositions mentioned above, more than one compound of formula (I) isimportant as it enables the perfumer to prepare accords, perfumes,possessing the odor tonality of various compounds of the invention,creating thus new tools for his work.

For the sake of clarity, it is also understood that any mixtureresulting directly from a chemical synthesis, e.g. a reaction mediumwithout an adequate purification, in which the compound of the inventionwould be involved as a starting, intermediate or end-product could notbe considered as a perfuming composition according to the invention asfar as said mixture does not provide the inventive compound in asuitable form for perfumery.

Furthermore, the invention's compound can also be advantageously used inall the fields of modern perfumery, i.e. fine or functional perfumery,to positively impart or modify the odor of a consumer product into whichsaid compound (I) is added.

Consequently, a perfuming consumer product which comprises:

i) as perfuming ingredient, at least one compound of formula (I), asdefined above; and

ii) a perfumery consumer base; is also an object of the presentinvention.

The invention's compound can be added as such or as part of aninvention's perfuming composition.

For the sake of clarity, it has to be mentioned that, by “perfumingconsumer product” it is meant a consumer product which is expected todeliver at least a perfuming effect, in other words it is a perfumedconsumer product. For the sake of clarity, it has to be mentioned that,by “perfumery consumer base” we mean here the functional formulation, aswell as optionally additional benefit agents, corresponding to aconsumer product which is compatible with perfuming ingredients and isexpected to deliver a pleasant odor to the surface to which it isapplied (e.g. skin, hair, textile, or home surface). In other words, aperfuming consumer product according to the invention comprises thefunctional formulation, as well as optionally additional benefit agents,corresponding to the desired consumer product, e.g. a detergent or anair freshener, and an olfactive effective amount of at least oneinvention's compound.

The nature and type of the constituents of the perfumery consumer basedo not warrant a more detailed description here, which in any case wouldnot be exhaustive, the skilled person being able to select them on thebasis of his general knowledge and according to the nature and thedesired effect of said product.

Non-limiting examples of suitable perfumery consumer base can be aperfume, such as a fine perfume, a cologne or an after-shave lotion; afabric care product, such as a liquid or solid detergent, a fabricsoftener, a fabric refresher, an ironing water, a paper, or a bleach; abody-care product, such as a hair care product (e.g. a shampoo, acoloring preparation or a hair spray), a cosmetic preparation (e.g. avanishing cream or a deodorant or antiperspirant), or a skin-careproduct (e.g. a perfumed soap, shower or bath mousse, oil or gel, or ahygiene product); an air care product, such as an air freshener or a“ready to use” powdered air freshener; or a home care product, such as awipe, a dish detergent or hard-surface detergent.

Some of the above-mentioned consumer product bases may represent anaggressive medium for the invention's compound, so that it may benecessary to protect the latter from premature decomposition, forexample by encapsulation or by chemically bounding it to anotherchemical which is suitable to release the invention's ingredient upon asuitable external stimulus, such as an enzyme, light, heat or a changeof pH.

The proportions in which the compounds according to the invention can beincorporated into the various aforementioned articles or compositionsvary within a wide range of values. These values are dependent on thenature of the article to be perfumed and on the desired organolepticeffect as well as the nature of the co-ingredients in a given base whenthe compounds according to the invention are mixed with perfumingco-ingredients, solvents or additives commonly used in the art.

For example, in the case of perfuming compositions, typicalconcentrations are in the order of 0.01% to 20% by weight, or even more,of the compounds of the invention based on the weight of the compositioninto which they are incorporated. Concentrations lower than these, suchas in the order of 0.01% to 5% by weight, can be used when thesecompounds are incorporated into perfumed articles, percentage beingrelative to the weight of the article.

The invention's compounds can be prepared according to a method asdescribed in the Examples.

EXAMPLES

The invention will now be described in further detail by way of thefollowing examples, wherein the abbreviations have the usual meaning inthe art, the temperatures are indicated in degrees centigrade (° C.);the NMR spectral data were recorded in CDCl₃ (if not stated otherwise)with a 360 or 400 MHz machine for ¹H and ¹³C, the chemical shifts δ areindicated in ppm with respect to TMS as standard, the coupling constantsJ are expressed in Hz.

The compounds not part of the invention but prepared for comparativespurposes were obtained as follows:

4-(2,6,6-trimethyl-5-methylene-3-cyclohexen-1-yl)-3-buten-2-one

Reaction 8→9

Peracetic acid (40%, 2.71 g, 14.3 mmol) was added dropwise to a stirredsuspension of 8 (3 g, 14.3 mmol) and NaOAc (0.7 g, 8.54 mmol) in CH₂Cl₂(30 mL) at 0-5° C. The mixture was stirred for 2 hours at roomtemperature and diluted with water (50 ml). The organic phase was washedwith Na₂CO₃ (10%) and brine, then distilled at 100° C./0.5 mbar to give2.5 g of epoxide 9 as a 4:1 mixture of diastereomers (77% yield).

Reaction 9→10

A solution of 9 (2 g, 8.85 mmol) in 5 ml of toluene was added dropwiseto a stirred solution of Al(i-OPr)₃ (0.35 g, 1.72 mmol) in toluene (20ml) at 100° C., then refluxed for 1 hour. After cooling the mixture, itwas washed with cold 10% H₂SO₄ and water, then chromatographed on silicato furnish 0.8 g of 94% alcohol 9 (40% yield).

Reaction 10→11

POCl₃ (2 g, 13 mmol) was added slowly to a stirred solution of 10 (1 g,4.42 mmol) in pyridine (7 ml) at room temperature. After 20 hours, thereaction mixture was poured onto ice/water very slowly then extractedwith ether, washed with 10% H₂SO₄, water, 5% NaHCO₃ and brine.Distillation (130° C., 0.5 mbar) furnished 11 (0.37 g, 65% purity=25%yield).

Reaction 11→12

Ester 11 was reduced with 0.5 molar equivalents of LiAlH₄, providingalcohol 12 in 88% yield.

Reaction 12→13

12 (1.88 g, 11.3 mmol) was oxidized with PDC (4.25 g, 11.3 mmol) tofurnish aldehyde 13 (1.1 g, 59% yield).

Reaction 13→14

A solution of Na (0.08 g, 3.48 mmol) in EtOH (3 ml) was added to amixture of 13 (0.4 g, 2.44 mmol), triethylphosphonoacetate (0.6 g, 2.68mmol) and petroleum ether 30/50 (10 mL) and refluxed for 4 hours. Aftercooling, the reaction mixture was poured onto ice/HCl (10%), washed withbrine, and distilled (150° C., 0.6 mbar) to furnish ester 14 (0.5 g, 88%yield) as a 1:1 mixture.

Reaction 14→15→16→17→18

A solution of ester 14 (0.49 g, 2.09 mmol) in ether (10 ml) was reducedwith LiAlH₄ (0.08 g, 2.11 mmol) to give alcohol 15 in 89% yield.Oxidation of alcohol 15 with PDC furnished aldehyde 16 in 87% yield.Aldehyde 16 was then reacted with MeMgI in ether to give 0.27 g ofalcohol 17 in 78% yield. Alcohol 17 was then reoxidized with PDC aspreviously to furnish 0.25 g of enone 18 (cis/trans=1:1). Prep GCfurnished the pure isomers.

¹H NMR (cis-18): 0.91 (d, J=7.2, 3H), 1.03 (s, 3H), 1.13 (s, 3H), 2.07(dd, J₁=4.8, J₂=10.7, 1H), 2.19 (s, 3H), 2.77 (br. s, 1H), 4.92 and 4.95(two s, 2H), 5.44 (d, J=10, 1H), 6.02 (d, J=16, 1H), 6.11 (dd, J₁=2.8,J₂=10, 1H), 6.37 (dd, J₁=9, J₂=16, 1H)

¹³C NMR (cis-18): 19.2, 26.6, 26.9, 28.8, 31, 37.7, 55.1, 111.7, 129,131.3, 134.2, 148.1, 149.3, 198.6

¹H NMR (trans-18): 0.95 (d, J=7.2, 3H), 1.03 (s, 3H), 1.06 (s, 3H), 1.86(tr., J=10.3, 1H), 2.28 (s, 3H), 4.82 and 4.97 (two s, 2H), 5.57 (d,J=10, 1H), 6.09 (dd, J₁=2.8, J₂=10, 1H), 6.1 (d, J=16, 1H), 6.68 (dd,J₁=10, J₂=16, 1H)

¹³C NMR (trans-18): 20.1, 23.1, 26, 27.4, 32.4, 37.2, 55.4, 109.6,128.3, 132.6, 134, 148.1, 151.9, 198.1

(E)-4-(4,6,6-trimethyl-1,3-cyclohexadien-1-yl)-3-buten-2-one

Aldehyde 19 (1.5 g, 10 mmol) and acetylmethylene-triphenylphosphorane(3.18 g, 10 mmol) in 30 ml of toluene was heated overnight in anautoclave to 180° C., then at 200° C. for 3 hours. The crude reactionmixture was chromatographed on silica to give 60 mg of pure 8.

¹H-NMR: 1.11 (s, 6H), 1.85 (s, 3H), 2.09 (s, 2H), 2.28 (s, 3H), 2.28 (s,3H), 5.78 (dd, J₁=6, J₂=1, 1H), 6.31 (d, J=6, 1H), 6.39 (d, J=15, 1H),7.21 (d, J=16, 1H)

¹³C NMR: 23.8, 26.6, 27.4, 34.1, 45.8, 119, 125.7, 127.1, 139, 140.7,143.1, 198.2

Example 1 Synthesis of Compounds of Formula (I) Synthesis of(E)-4-(2,5,6,6-tetramethylcyclohexa-1,3-dienyl)but-3-en-2-one Step 1

A 3-neck 11 round bottom flask equipped with a condenser, thermometerand magnetic stir bar was charged with 115 g of pulverized maleicanhydride (1.17 mol), 150 g of aldehyde 1 (0.9 mol) and 435 ml ofCH₂Cl₂. The solution was agitated under an atmosphere of N₂ and cooledto 10° C. with an ice water bath. Upon reaching the desired temperature,64 g of 56% H₂O₂ (1.05 mol) was introduced with a syringe pump over aperiod of 1 hour. During the introduction, the reaction exothermed to36° C. and solid precipitate was formed. The slurry was stirred for anadditional 5 hours at room temperature to 96% conversion of aldehyde 1into epoxide 2. The slurry was then diluted with approximately 500 ml oftoluene and filtered using a Buchner funnel. The solid was discarded andthe filtrate was concentrated on the rotovapor to remove most of themethylene chloride. The methylene chloride-free solution containing thecrude epoxide 1 in toluene was then charged with 25 g of K₂CO₃ (0.18mol) and brought to reflux. After 5 hours of reaction, epoxide 1 wascompletely converted to allylic alcohol 3 and the reaction mixture wascooled to room temperature and washed twice with 200 mL of water toneutral pH. After removing the toluene under reduced pressure with therotovapor, 165 g of crude alcohol 3 was obtained. The latter was thendistilled using a small vigreux column at 1-2 mbar, collecting 124 g of98% pure allylic alcohol 1 at a vapor temperature of 109-115° C. Yieldfor 3 based on 1, 76%.

Step 2

A 3-neck 250 ml round bottom flask equipped with a magnetic stir bar andreflux condenser was charged with 38 g of allylic alcohol 3 (0.22 mol),0.53 g of N,N-dimethylamino pyridine (0.004 mol) and 58 g of toluene.The mixture was heated to 50° C. and then charged with 24 g of aceticanhydride (0.24 mol) over a 20 minute period. During the addition, thereaction exothermed to 60° C. before dropping to 55° C. at the end ofthe addition. Fifteen minutes after the end of the addition, GC analysisshowed the complete conversion of starting material into acetate 4. Thereaction mixture was cooled to room temperature and carefully pouredinto 288 g of saturated NaHCO₃. After neutralizing the acetic acid, themixture was phase separated and the organic layer was concentrated undervacuum to obtain 42 g of crude acetate 4 at 96% purity and used for thenext step without further purification.

A 3-neck 250 ml round bottom flask equipped with a magnetic stir bar andreflux condenser was charged with 28 g of crude acetate 4 (0.13 mol),0.42 g of Pd[P(C₆H₅)3]₄ (0.00036 mol), 15.2 g of Et₃N (0.15 mol) and 84g of toluene. The solution was refluxed under N₂ for 1 hour to completeconversion. After cooling the reaction mixture to room temperature, itwas washed with 10% H₃PO₄, followed by saturated NaHCO₃ and finallywater to pH 7. After concentrating the organic layer, 21.5 g of crudealdehyde 5 was obtained at 89% purity. The latter was distilled with thekuegel-rohr to give 16.2 g of 95% pure aldehyde 5 (72% yield from 4,overall 68% yield from alcohol 3) along with 2.1 g of residue.

Step 3

A 3-neck 100 ml round bottom flask equipped with a magnetic stir bar andreflux condenser was charged with 0.098 g of LiOH monohydrate (0.0023mol), 68 g of acetone (1.17 mol) and 14 g of water. The mixture wasbrought to reflux then charged with 10 g of aldehyde 5 (96%, 0.058 mol)over a 1 hour period. The solution was refluxed for 9 hours to 97%conversion and then cooled to room temperature and neutralized with 1.8g of 5% H₃PO₄. The reaction mixture was diluted with 80 g of heptane andphase separated. The aqueous phase was extracted twice with 15 g ofheptane and the extracts combined with the original organic phase.Following concentration on the rotovapor, 14.3 g of crude concentratewas obtained, which was subsequently distilled on the kuegel-rohr togive 11.53 g of distillate containing ketone(E)-4-(2,5,6,6-tetramethylcyclohexa-1,3-dienyl)but-3-en-2-one at 87%purity (83% yield). The latter was further distilled on a 12.5 cmvigreux column to obtain 7.7 g of 94% pure material distilling at 77-78°C. at 0.5 mbar.

¹H-NMR: 0.94 (1H, d, J=7), 0.98 (3H, s), 1.08 (3H, s), 1.88 (3H, s),2.06-2.15 (1H, m), 2.31 (3H, s), 5.72-5.76 (1H, dd, J=9, J=4), 5.80 (1H,doublet, J=9), 6.17 (1H, doublet, J=16), 7.25 (1H, doublet, J=16)

¹³C NMR: 14.4, 20.71, 21.38, 26.67, 27.69, 37.70, 40.92, 128.18, 131.23,131.82, 135.49, 135.99, 142.92, 198.73

Synthesis of 4-(2,5,6,6-tetramethylcyclohexa-1,3-dienyl)butan-2-one

A 3-neck 50 ml round bottom flask equipped with a magnetic stir bar andreflux condenser was placed under N₂ and charged with 1 g of water (53mmol), 2.2 g of NH₄Cl (41 mmol), 28 g of THF, 4 g of enone(E)-4-(2,5,6,6-tetramethylcyclohexa-1,3-dienyl)but-3-en-2-one (19.6mmol) and 0.3 g of Pd(PPh₃)₄ (0.26 mmol). With stirring on, 5.7 g ofSnBu₃H (19.6 mmol) was introduced over a 1 hour period at roomtemperature and stirred for another 4.5 hours until about 6% startingmaterial remained. The reaction mixture was diluted with 100 ml of TAME,phase separated, washed with 50 ml of brine and concentrated on therotovapor. The crude concentrate was rediluted with 50 g of EtOAc,poured into a 50 g solution of 50% KF and stirred for 4 hours. Themixture was phase separated and the organic layer was concentrated onthe rotovapor to give 8 g of crude. The latter was columnchromatographed on silica gel 60 (80:20 heptane/isopropyl ether) to give2.6 g of 92% pure ketone4-(2,5,6,6-tetramethylcyclohexa-1,3-dienyl)butan-2-one (61% yield).

¹H-NMR: 0.89 (3H, s), 0.91 (1H, d, J=8), 1.04 (3H, s), 1.69 (3H, s),2.02 (1H, m), 2.17 (3H, s), 2.36 (2H, t, J=8), 2.51 (2H, t, J=8), 5.5(1H, dd, J=9, J=4), 5.65 (1H, dd, J=10, J=1)

¹³C NMR: 14.1, 18.0, 20.1, 22.3, 26.1, 29.9, 37.8, 40.6, 43.6, 125,127.6, 130.9, 137.5, 208.5

Example 2 Preparation of a Perfuming Composition

A perfuming composition, of the woody type, was prepared by admixing thefollowing ingredients:

Parts by weight Ingredient 60 Benzylacetone 20 Cashmeran ®¹⁾ 100Castoreum oil 10 Cetalox ®²⁾ 350 10%** Civettine 150 Cypriol 200(1′R,E)-2-Ethyl-4-(2′,2′,3′-trimethyl-3′-cyclopenten-1′-yl)-2-buten-1-ol³⁾ 202-Methyl-4-(2,2,3-trimethyl-3-cyclopenten-1-yl)-4- penten-1-ol³⁾ 110Gaiac 80 Methylionone Beta 20 Methylnaphthylcetone 80 10%* Dextro3-methyl-5-cyclopentadecen-1-one³⁾ 20 10%* Myrrhone ®⁴⁾ 20 Safranal 500Santal 10 10%* Scatol 1750 *in dipropyleneglycol **in ethyl citrate¹⁾1,2,3,5,6,7-hexahydro-1,1,2,3,3-pentamethyl-4-indenone; origin:International Flavors & Fragrances, USA²⁾dodecahydro-3a,6,6,9a-tetramethyl-naphtho[2,1-b]furan; origin:Firmenich SA, Geneva, Switzerland ³⁾origin: Firmenich SA, Geneva,Switzerland ⁴⁾4-(2,2,c-3,t-6-tetramethyl-R-1-cyclohexyl)-3-buten-2-one;;origin: Firmenich SA, Geneva, Switzerland

The addition of 250 parts by weight of(E)-4-(2,5,6,6-tetramethylcyclohexa-1,3-dienyl)but-3-en-2-one to theabove-described woody/agarwood composition reinforced the spicy-saffronaspect and conferred a unique warm powdery effect absent from the abovecomposition.

The addition of the same amount of ionones or irones imparted totallydifferent effect, devoid of any spicy reinforcement and unable to imparta warm powdery effect.

Example 3 Preparation of a Perfuming Composition

A perfuming composition for a soap, of the floral spicy type, wasprepared by admixing the following ingredients:

Parts by weight Ingredient 50 Dimethyl benzyl carbinyl acetate 20Styrallyl acetate 20 C 11 Undecylenic aldehyde 100 Hexylcinnamicaldehyde 250 Citronellol 100 4-Cyclohexyl-2-methyl-2-butanol¹⁾ 70Coumarine 40 Eugenol 102-Methyl-4-(2,2,3-trimethyl-3-cyclopenten-1-yl)-4- penten-1-ol¹⁾ 100Geraniol 80 Hedione ®²⁾ 30 Heliotropine 40 Helvetolide ®³⁾ 40 10%*Isobutylquinoleine 20 Isoeugenol 90 Isoraldeine gamma 150 Lorysia ®⁴⁾ 2010%* Neobutenone ®⁵⁾ Alpha 10Trans-1-(2,2,6-trimethyl-1-cyclohexyl)-3-hexanol¹⁾ 40 Patchouli oil 150Phenethylol 40 Wardia ®⁶⁾ Rose 50 Rosinol 100 Amyl salicylate 50Sclareolate ®⁷⁾ 80 Terpineol 10 Gamma undecalactone 150 Vertofix ®⁶⁾Cœur 40 Ylang 1950 *in dipropyleneglycol **in isopropyle myristate¹⁾origin: Firmenich SA, Geneva, Switzerland ²⁾Methylcis-dihydrojasmonate; origin: Firmenich SA, Geneva, Switzerland³⁾(1S,1′R)-2-[1-(3′,3′-dimethyl-1′-cyclohexyl)ethoxy]-2-methylpropylpropanoate; origin: Firmenich SA, Geneva, Switzerland⁴⁾4-(1,1-dimethylethyl)-1-cyclohexyl acetate; origin: Firmenich SA,Geneva, Switzerland ⁵⁾1-(5,5-dimethyl-1-cyclohexen-1-yl)-4-penten-1-one;origin: Firmenich SA, Geneva, Switzerland ⁶⁾Compounded perfumeryspecialty; origin: Firmenich SA, Geneva, Switzerland ⁷⁾Propyl(S)-2-(1,1-dimethylpropoxy)propanoate; origin: Firmenich SA, Geneva,Switzerland ⁸⁾Methyl cedryl ketone; origin: International Flavors &Fragrances, USA

The addition of 50 parts by weight of(E)-4-(2,5,6,6-tetramethylcyclohexa-1,3-dienyl)but-3-en-2-one to theabove-described composition reinforced the spicy-aspect by imparting asaffron note which conferred to the new perfuming composition a newtwist, almost curry type, and reinforced also powdery aspects of theinitial composition.

The addition of the same amount of ionones or irones did not modify thespicy notes of the initial composition.

What is claimed is:
 1. A method to confer, enhance, improve or modify the odor properties of a perfuming composition or of a perfumed article, which method comprises adding to said composition or article an effective amount of at least a compound of formula

in the form of any one of its enantiomers or a mixture thereof, and wherein the bond between the two carbons connected by the dotted line being a single or double bond having predominantly a configuration E; to impart odor notes of the saffron type together with aspects of the methylionone/orris type.
 2. A method according to claim 1, wherein said compound is 4-(2,5,6,6-tetramethylcyclohexa-1,3-dienyl)-but-3-en-2-one.
 3. A method according to claim 1, wherein said compound is (E)-4-(2,5,6,6-tetramethylcyclohexa-1,3-dienyl)-but-3-en-2-one.
 4. A compound of formula

in the form of any one of its enantiomers or a mixture thereof, and wherein the bond between the two carbons connected by the dotted line being a single or double bond having predominantly a configuration E.
 5. A perfuming composition comprising i) at least one compound of formula (I), as defined in claim 1; ii) at least one ingredient selected from the group consisting of a perfumery carrier and a perfumery base; and iii) optionally at least one perfumery adjuvant.
 6. A perfuming consumer product comprising: i) at least one compound of formula (I), as defined in claim 1; and ii) a perfumery consumer base.
 7. A perfuming consumer product according to claim 6, wherein said perfumery consumer base is a perfume, a fabric care product, a body-care product, an air care product or a home care product.
 8. A perfuming consumer product according to claim 6, wherein said perfumery consumer base is a fine perfume, a cologne, an after-shave lotion, a liquid or solid detergent, a fabric softener, a fabric refresher, an ironing water, a paper, a bleach, a shampoo, a coloring preparation, a hair spray, a vanishing cream, a deodorant or antiperspirant, a perfumed soap, shower or bath mousse, oil or gel, a hygiene product, an air freshener, a “ready to use” powdered air freshener, a wipe, a dish detergent or hard-surface detergent. 